1. Field of the Invention
The present invention relates to a tool extension bar and, more particularly, to a tool extension bar suitable to have an application with a power tool and adapted to be connected to or disconnected from a tool member, such as a socket.
2. Description of the Related Art
U.S. Pat. No. 8,070,377 discloses a tool extension bar including a rod, a sleeve, a ball, and a spring. The rod has first and second sections. The first section of the rod includes an end for coupling with a pneumatic tool, and the second section of the rod extends from the other end of the first section. The sleeve is slideably mounted around the rod and includes an end for releasably coupling a bit. The sleeve includes an axial bore having larger and smaller sections. The larger section of the sleeve has polygonal cross sections corresponding to polygonal cross sections of the first section. A radial bore is formed in the sleeve and in communication with the smaller section. The ball is moveably received in the radial bore and moveably received in a recess of the second section of the rod to releasably engage the sleeve with the bit. The spring is mounted in the larger section of the axial bore of the sleeve and biases the sleeve from the retracted, second position to the extended, first position. The ball is engaged in the first contact section of the recess with an outermost portion of the ball projecting out of the radial bore of the sleeve when the sleeve is in the extended, first position, coupling the bit with the second end of the sleeve. The ball is engaged in the second contact section of the recess and does not project out of the radial bore of the sleeve when the sleeve is in the retracted, second position, allowing the bit to be disengaged from the second end of the sleeve.
However, the tool extension bar used with the pneumatic tool has some disadvantages. The pneumatic tool driven by a gas, usually compressed air supplied by a gas compressor, will certainly create vibration in operation. Thus, the spring is repeatedly retracted and extended to cause the sleeve to change from the first position to the second position. Therefore, the bit will disengage from the second end of the sleeve unintentionally.
Moreover, a user must grip on the end of the sleeve coupling to the bit and move the sleeve to cause the sleeve to move relative to the rod in the axial direction from the first position to the second position to allow the bit to be disengaged from the end of the sleeve. If the total length of the tool extension bar is very long, the user can not use it comfortably and can not grip the tool extension bar efficiently. In other words, it is not ergonomic.
The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art.